9 PIN DSUB ??
| Pin | Name (Select=GND) | Name (Select=+5V) | 
|---|---|---|
| 1 | Up | Up | 
| 2 | Down | Down | 
| 3 | Gnd / Left | |
| 4 | Gnd / Right | |
| 5 | +5VDC | +5VDC | 
| 6 | Button A | Button B | 
| 7 | Select | Select | 
| 8 | Ground | Ground | 
| 9 | Start | Button C | 
The chip inside the controller is a 74HC157. This is a high-speed cmos quad 2-line to 1-line multiplexer. The console can with help of the Select-pin choose from two functions on each input.
| Contributor: | Joakim Ögren, Neal Patrick Howland | 
| Source: | SEGA Genesis A/V pinout at GamesX | 
  Copyright © The Hardware Book Team 1996-2004.
  May be copied and redistributed, partially or in whole, as appropriate.
  Document last modified: 2002-01-10